The bottom corners show the photo's capture age and EXIF location. This one was taken in Palmeiras two years ago.
## Why Most digital frames either require you to pick and preprocess photos that you put on an SD card or they want to talk to a cloud service like Google Photos. Realistically, you're not going to update the photos more than once a year on the SD card. As for cloud providers, I'd rather not give them access to my cherished memories or let them be held hostage. -It's magical to come home from a day out to immediately see photos taken from the day, or see memories from years ago pop up within the living space, unconfined by an app on your phone. +Coming home to a photo from earlier that day, or one from five years ago, hits differently when it's just sitting on the wall instead of buried in your phone. It was a fun afternoon project with Claude Code, a bit of experimenting with different dithering and post-processing, and then fine tuning the photo picking algorithm. Besides powering my frame, I share this repo as a reference and as inspiration for self-hosting, to show that the combination of these services can produce something that otherwise wouldn't have been possible to hack together so quickly. @@ -18,8 +19,8 @@ It was a fun afternoon project with Claude Code, a bit of experimenting with dif 1. Quits if it's between midnight and 7am. 2. Asks Home Assistant whether anyone in `HA_PRESENCE` is home. If not, quits to preserve power and not strain the e-ink unnecessarily. -3. Picks a random photo from Immich, weighted toward "on this day" memories, favourites, and recent uploads (see [immich.py](./src/lib/immich.py)). -4. Crops around any detected faces, applies post-processing to boost contrast and saturation (which are both lacking in e-ink displays), dithers down to the 6-colour palette, and pushes it to the panel. +3. Picks a random photo from Immich. The pool is weighted: ~30% "on this day" memories (10% if only the ±3-day fallback fires), ~18% favourites, ~36% the last 30 days, and ~36% everything else. A 7-day rolling history avoids repeats; orientation match gets 4x the weight of mismatch. See [immich.py](./src/lib/immich.py). +4. Crops around any detected faces, boosts contrast and saturation (both lacking on e-ink), dithers down to the 6-colour palette, and pushes it to the panel. The capture age and EXIF location are painted into the bottom corners as white-on-black-stroke text, so dithering can't smear the edges. ## Image pipeline @@ -27,7 +28,7 @@ The two choices that matter most are `face_aware_crop` and Atkinson dithering. ### Cropping -The frame has one orientation but I didn't want to limit it to only show portrait or landscape photos. So the `face_aware_crop` function resize-crops to fill the frame while keeping all faces within the frame. This can nicely turn a landscape with extra background into a crop that works well on the portrait frame. For finding faces, it relies on the bounding boxes returned by Immich. +Obviously, the frame can only be in orientation at a time but I didn't want to limit it to only show portrait or landscape photos. So the `face_aware_crop` function resize-crops to fill the frame while keeping all faces within the frame. A landscape shot with room around the subject usually crops cleanly to portrait this way. For finding faces, it relies on the bounding boxes returned by Immich. See the following example from [crop_compare.ipynb](./notebooks/crop_compare.ipynb) that shows how the head bounding boxes affect the final crop. @@ -35,13 +36,15 @@ See the following example from [crop_compare.ipynb](./notebooks/crop_compare.ipy
-The second issue is the limited 6-colour palette. The intensity of these colours can't be changed like on an LCD panel, they're either shown or not. So to get any legible results, we have to turn to dithering. Turns out, there are many dithering algorithms with wildly different running times. [dither_compare.ipynb](./notebooks/dither_compare.ipynb) shows a comparison between a few.
+### Dithering
+
+The panel can only show six colours: black, white, red, yellow, blue, and green. There's no intensity control like on an LCD, every pixel is one of those six. To get anything legible we have to dither, and there are many algorithms with wildly different running times. [dither_compare.ipynb](./notebooks/dither_compare.ipynb) shows a comparison between a few.
